1. Technical Field
The present disclosure relates to an apparatus for penetrating body tissue, and, more particularly, to a trocar having an obturator responsive to actuation of a trigger mechanism. The present disclosure further relates to a handle assembly to which various ports, trocars and other devices can be attached and which incorporates a trigger mechanism that can drive several different functions of the various attachments.
2. Description of Related Art
Endoscopic surgical procedures, that is, surgical procedures performed through tubular sleeves or cannulas, have been utilized for many years. Initially, endoscopic surgical procedures were primarily diagnostic in nature. More recently as endoscopic technology has advanced, surgeons are performing increasingly complex and innovative endoscopic surgical procedures. In endoscopic procedures, surgery is performed in any open space in the body through natural openings, a small incision or through narrow endoscopic tubes (cannulas) inserted through small entrance wounds in the skin. In laparoscopic procedures, surgery is performed in the interior of the abdomen.
Laparoscopic procedures generally utilize instrumentation that is internally sealed to inhibit gases from entering or exiting the body through the laparoscopic or endoscopic incision. This is particularly true in surgical procedures in which the surgical region is insufflated. Moreover, laparoscopic and endoscopic procedures often require the surgeon to act on organs, tissues and vessels far removed from the incision, thereby requiring that any instruments to be used in such procedures be of sufficient size and length to permit remote operation.
In accordance with laparoscopic surgical procedures, the abdominal cavity is insufflated with a suitable gas such as CO.sub.2. Thereafter, a trocar is employed to puncture the abdominal wall. Generally, a conventional trocar includes an obturator having a sharp obturator tip for penetrating the body cavity and a protective sleeve in which the obturator is coaxially positioned. The trocar also includes or, is used in combination with, a cannula which remains in place for use during the surgery. An example of a known trocar is described in commonly assigned U.S. Pat. No. 4,601,710 to Moll.
Although conventional trocars have been generally effective for their intended purposes, it has become apparent that certain improvements and modifications can be made to existing trocars to more adequately adapt the trocar for laparoscopic surgery. In particular, one disadvantage with known trocars and their uses concerns the difficulty encountered by the surgeon in controlling the penetrating movement of the trocar through the body wall as well as the force required on behalf of the surgeon to achieve such penetration. In applying a conventional trocar, the surgeon typically grasps the proximal end or housing portion of the trocar and exerts a downward force to cause penetration of the obturator tip through the body tissue, e.g., the abdominal wall and peritoneal lining. Since the force required to achieve penetration through the abdominal wall is relatively high, e.g., 5-15 lbs., the momentum generated during such penetration may carry the obturator tip into engagement with underlying tissue or viscera if the surgeon is not careful.
Another disadvantage with known trocars is that prior to application of the trocar an incision must be made with a scalpel or similar instrument in the outer skin tissue to facilitate the subsequent positioning of the trocar and penetrating movement into the abdominal cavity. Thus, the requirement of the incision adds another step and device to the surgical procedure. Moreover, often times the incision is imprecise in that it is inappropriately too large or too small for the obturator tip. An oversized incision will negatively affect the integrity of the seal formed about the cannula with the adjacent body tissue and may increase the risk of bleeding at the incision site. An undersized incision will result in possible tissue tear during application and penetration of the obturator tip. Even further, the undersized tissue can ultimately lead to necrosis of the tissue compressed around the cannula by stopping the blood flow.
A further disadvantage with known trocars concerns the shape and dimension of the formed incision. The obturator tip of a conventional trocar typically is pyramidally-shaped which provides an arcuate incision or opening in the body cavity wall. An arcuate incision or opening is less desirable than a linear incision since an arcuate incision generally entails a lengthier recovery time and does not heal as neatly as compared to linear incisions.
Accordingly, there exists a need for a trocar incorporating structure which enhances control of the trocar and which facilitates the penetrating action of its penetrating tip. There also exists a need for a trocar having tissue cutting structure which obviates the need for an initial incision to be made in the outer skin tissue with a separate device. There further exists a need for a trocar having tissue cutting structure which forms a generally linear incision in the body wall. There further exists a need for a trocar that is capable of both sharp and blunt dissection.